The invention relates to apparatus for carrying our peritoneal dialysis and measuring the amount of fluid which is withdrawn from the patient in such a process.
The usual process for peritoneal dialysis comprises introducing a given amount of a flushing fluid through a catheter which is inserted into the abdominal cavity of the patient, and then emptying the fluid subsequently, possibly after a given period of waiting. This process is repeated several times in the course of a treatment. Because of osmotic effects, the amount of fluid which flows out is generally somewhat greater than the amount of fluid which is introduced. Measuring the additional amount of fluid which is removed is of considerable interest in regard to judging the treatment.
In the previously known peritoneal dialysis apparatus, some cases do not carry out a balancing operation, that is to say, they do not determine the additional amount of fluid which is drained off. In some cases, balancing is carried out in a form such that the amount of fluid introduced is metered by means of a balance which is provided with a switching contact, while the amount of fluid which is emptied out is collected in a measuring beaker and the amount thereof must be read off by an operator in order thereby to determine the difference. Apart from the lack of precision which can result from the different nature of the measuring processes (measuring by weight and measuring by volume) and from possible errors in reading off the result, this process and evaluation of the readings are very labour-intensive. Other forms of apparatus avoid this by using volumetric monitoring both of the amount of fluid which is introduced and the amount of fluid which is removed, by means of measuring chambers of constant volume with incorporated level electrodes, but this is liable to trouble for example due to the possibility of foam forming in the measuring chambers, while the fact that the apparatus is fixed on a given filling volume represents a certain limitation. Another known apparatus operates with variable volumetric metering or measurement of the amounts of fluid which flow in and out of the patient, and thus avoids a disadvantage of the previous apparatus, but this process has also not met with practical success because of the high expenditure and the resulting liability to trouble.
The present invention is based on the problem of providing a peritoneal dialysis apparatus which permits the additional amount of fluid which flows out of the patient to be precisely determined by simple technical means and without precision measuring devices. This is achieved by a particularly simple use involving the features recited in the claims.